Plastic sheeting made of acrylonitrile-containing polymers, and particularly poly(acrylonitrile-butadiene-styrene), are used to make cups and other containers which may be easily made from sheeting by thermoforming, stamping, or the like. These cups and containers also exhibit a desirably low permeability to oxygen and water vapor, and as such are desirable for use as containers for food and beverage, among other uses.
However, recent concern has arisen with respect to the possibility that nitrile-containing materials can migrate into the contents of the container. This concern is particularly focused upon containers intended for food and beverages. At the same time, the well-known hydrocarbon polymers such as polystyrene are excessively permeable to oxygen and water vapor for many types of use, for example, for storing margarine or other perishable foods.
Accordingly, there is a need for a container which exhibits a low vapor permeability, and at the same time prevents the possible migration of nitrile-containing molecules into the contents of the container.